In the field of containers for foodstuffs, and in particular for coffee, non-pressurized (where the internal pressure is equal to atmospheric pressure) or de-pressurized (where the internal pressure is less than atmospheric pressure) cylindrical containers are known. They comprise a cylindrical shell or central body, made of multi-joined flexible material, which is attached by means of welding at the lower part to a disc-shaped bottom, also made of multi-joined flexible material, and at the upper part to a lid made of peelable plastic material, welded onto an upper ring made of rigid plastic material, which in turn is welded on the shell. The bottom of the container is sometimes provided with a venting valve, normally of the mono-directional type, to allow air to escape to the outside.
These known containers are used in the home to contain foodstuffs, both liquid and solid, such as for example coffee, in beans, in powder or in pods. In this case, to guarantee the correct conditions for preserving the coffee, multi-joined flexible materials of a known type are usually used, with 3 or 4 layers, and inert and non-toxic gas is introduced inside the container. In this way, however, the package in its entirety keeps the characteristics of the foodstuff substantially unaltered (the so-called “shelf life”) for a maximum of 12 months, and with an internal oxygen residue of 3%.
In the state of the art, in order to create a barrier against the oxygen, the following components are usually used:                for the central body: multi-joined flexible material consisting of the following 4 layers: OPP 30-40μ; PET 12μ; Alu 8μ; PP 70-90μ;        for the bottom: multi-joined flexible material consisting of the following 3 layers: PETP 12μ; Alu 8μ; PP 200μ;        for the lid: semi-rigid material consisting of the following 3 layers: PP 250μ; EVOH 18μ; PP 250;        for the upper ring: PP.        
In the state of the art the different components of the container are welded to each other as follows:                the longitudinal edges of the central body: heat welding;        the bottom to the central body: ultrasound welding;        the lid to the upper ring: ultrasound welding;        the pre-assembled whole consisting of the lid and the upper ring on the central body: heat welding;        the valve to the bottom: gluing.        
Furthermore, in the state of the art, the following plastic components are made using the following techniques:                the lid: thermoform molding;        upper ring: injection molding.        
One disadvantage of these known containers is that the rigid upper ring is usually made of materials like PP, without an oxygen barrier, so that, since it has parts exposed to the air, it becomes a preferential channel for the entry of atmospheric oxygen inside the container itself, with a consequent deterioration of the foodstuff contained inside, for example the coffee may go rancid.
Another disadvantage of these known containers is the pressure generated inside the container by the foodstuff itself, in particular coffee, combined with that of the inert gas, even if it does not prejudice the airtight seal of known weldings (of the heat and ultrasound type), but only if it remains below 150 mbar. Furthermore, as a result of the internal depression, following high-altitude transport, the known container can implode, prejudicing the cylindrical shape and the aesthetic result.
Another disadvantage of these known containers is that the valve, if present, located on the bottom of the container, by venting the pressure inside the container, also causes the aromas inside to come out, and does not guarantee a residual internal pressure so that the aromatic components can be optimally attached inside the granules of coffee powder.
US 2008/105698 describes a container for foodstuffs, in particular coffee, with a central body made of flexible material, a bottom and a lid, where the lid is associated with the upper end of the central body by means of an upper ring made of rigid plastic material.
One purpose of the present invention is to obtain a container for foodstuffs, in particular but not exclusively coffee, for example of the cylindrical type, which is flexible, pressurized, hermetically sealed, which not only overcomes the disadvantages of the state of the art but is also safe, reliable and inexpensive, so as to guarantee optimum preservation, possible aging or maturing and a qualitative improvement of the foodstuff, for example coffee, contained therein, and which also guarantees to maintain its entirety and integrity for a long period of time, more than 12 months.
Another purpose of the present invention is to obtain a container that can be used both as an autonomous receptacle for containing foodstuffs, and also as a refill for another container for foodstuffs, for example stronger, like the known cans made of tin.
Another purpose of the present invention is to perfect a method for the production of a container for foodstuffs, in particular but not exclusively coffee, using non-toxic, plastic and metal multi-joined materials, which is economical, simple and reliable.
Another purpose of the present invention is to perfect a method for packaging a foodstuff, in particular but not exclusively coffee, inside said container, which guarantees optimum preservation conditions of the product and also an optimum airtight seal, with a barrier against the entry of oxygen from the outside, less than 1.5%, so as to achieve a shelf life of more than 12 months.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.